Patent Application
20180082799
The present disclosure relates to electrical switching apparatus, and more particularly to terminal barriers for electrical switching apparatus.
Electrical switching apparatus, such as circuit breakers, may include one or more electrical line terminals to which one or more line field electrical wires may be connected. In three-phase circuit breakers, for example, three line terminals may be included. During installation of the line-side terminal connection(s), the one or more field wires may be stripped, inserted into the terminal socket(s), and secured in place with terminal screw(s).
In operation, the circuit breaker ensures current interruption thereby providing protection to the electrical circuit from continuous over current conditions and high current transients due, for example, to electrical short circuits. To prevent electrical shock, sometimes, the line side of such circuit breakers may include a terminal barrier to prevent an installer/user/person from contacting any of the one or more stripped field wires and/or terminal screws.
However, such terminal shields are flawed in some aspects, as will be apparent from the following. Accordingly, there is a need for a terminal barrier that provides suitable terminal protection yet overcomes the problems of the prior art.
According to a first aspect, a terminal barrier assembly for one or more electrical terminals of an electrical switching apparatus is provided. The terminal barrier assembly includes a first barrier portion including a first opening portion, and a second barrier portion including a second opening portion, wherein the first opening portion and second opening portion interface with one another to form a shielding aperture configured for shielding around a line wire extending from the one or more electrical terminals.
In accordance with another aspect, an electrical switching apparatus is provided. The electrical switching apparatus includes a molded case housing including a first end and a second end, one or more electrical terminals located at the first end, and a terminal barrier assembly coupled to the first end, comprising: a first barrier portion including a first opening portion, and a second barrier portion including a second opening portion, wherein the first opening portion and second opening portion interface with one another to form a shielding aperture configured for shielding around a wire coupleable to an electrical terminal of the one or more electrical terminals.
In accordance with another aspect, a method of assembling an electrical switching apparatus is provided. The method includes providing a molded case housing of the electrical switching apparatus including an end receiving one or more electrical terminals, and coupling a terminal barrier assembly to the end, the terminal barrier assembly including a first barrier portion including a first opening portion, and a second barrier portion including a second opening portion, wherein the first opening portion and second opening portion interface with one another to form a shielding aperture configured for shielding around a wire extendable from the one or more electrical terminals.
Still other aspects, features, and advantages of the present disclosure may be readily apparent from the following detailed description by illustrating a number of example embodiments, including the best mode contemplated for carrying out the present invention. The present invention may also be capable of other and different embodiments, and its several details may be modified in various respects, all without departing from the scope of the present disclosure. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. The invention is to cover all modifications, equivalents, and alternatives falling within the scope of the claims as appended below.
The drawings, described below, are for illustrative purposes only and are not necessarily drawn to scale. The drawings are illustrative and not intended to limit the scope of the invention in any way. Wherever possible, the same or like reference numbers will be used throughout the drawings to refer to the same or like parts.
In one aspect, the terminal barrier assembly is operational to block off access to the stripped portion of the wire (e.g., a line-side wire otherwise referred to herein as a “line wire”) and also to the one or more electrical terminals so that a user cannot come into contact with either the stripped portion of the wire or the electrical terminal. However, the wire may be of any number of different sizes (e.g., of different diameters). Prior art terminal barrier assemblies may be ineffective at providing a barrier of all possible sizes of line wires. Thus, in accordance with one aspect, a terminal barrier assembly is provided that accommodates different sizes of wires (e.g., line wires), yet still provides an adequate barrier and shock protection. Embodiments of the terminal barrier assembly may include flexible fingers that contact the wire. The flexible fingers may flex against an outside portion of the wire (e.g., against the wire insulation) upon entry into the terminal thus accommodating different sizes of wire. The terminal barrier assembly may be configured to accommodate wire sizes between about #3 AWG to about 300 kcmil copper or aluminum wire, for example.
In another aspect, it may be desirable to inspect the electrical terminal connection after a wire is installed into a terminal block and the terminal screw is secured. Thus, according to one or more embodiments, a terminal barrier assembly is provided that readily allows inspection of the terminal connection(s), such as electrical line wire connections to a line terminal(s). In particular, in one or more embodiments, a multi-piece terminal barrier assembly is provided. The multi-piece terminal barrier assembly may include a first barrier portion and a second barrier portion. The portions may interface with one another to form one or more shielding apertures that are configured to receive the terminal wire (e.g., line wire) therein when the wire is connected to the electrical terminal. The portions interface with one another and are separable from one another so that at least one of the portions is readily removable to allow for a visual inspection of the electrical terminal connection. In other embodiments, both of the portions are removable.
Terminal barrier assemblies, electrical switching apparatus including the terminal barrier assembly, and methods of assembling the terminal barrier assembly to an electrical switching apparatus according to one or more embodiments of the present invention are described below with reference to
Referring now to
The housing 106 may be made up of any number of interconnecting housing sections. For example, two housing halves may make up the first housing portion 106A and the second housing portions 106B, which may be connected together (e.g., by rivets) to form the housing 106 and to form an internal cavity (not shown) for receiving an electrical contact assembly, tripping mechanism, and other electrical components (all not shown). Conventional circuit breaker components may include the electrical contact assembly, tripping mechanism, load terminal(s), a bimetal assembly, a latch, and a cradle, and a handle, which are entirely conventional and will not be explained in further detail.
In the depicted embodiment, the housing 106 includes a first end 108A and second end 108B. According to one or more embodiments of the invention, the terminal barrier assembly 104 may be configured for use with one or more terminals of an electrical switching apparatus 100. For example, in the depicted embodiment, the terminal barrier assembly 104 may be coupled to the first end 108A including one or more line terminals. However, it should be understood that the terminal barrier assembly 104 may be used on the second end in some installations, i.e., to provide a shielding barrier for load side electrical terminals.
The terminal barrier assembly 104 includes a first barrier portion 110 including a first opening portion 112A, such as adjacent to a bottom end, and a second barrier portion 114 including a second opening portion 112B, such as adjacent to a top end, wherein the first opening portion 112A and second opening portion 112B interface with one another to form one or more shielding apertures 112. The one or more shielding apertures 112 are configured for shielding around one or more line wires 116 extending from the one or more line terminals 118 as is shown in
In the depicted embodiment, the terminal barrier assembly 104 includes three shielding apertures 112. However, the terminal barrier assembly 104 may include a lesser number of shielding apertures 112, such as two or more shielding apertures configured for shielding around two or more electrical wires (e.g., two or more line wires 116). For example, for a two-pole switching apparatus, such as a two-pole circuit breaker, two shielding apertures 112 may be provided. In another example, a single one of the shielding aperture 112 may be provided for a one-pole switching apparatus, such as a single-pole circuit breaker.
As illustrated, the electrical switching apparatus 100 may have coupled to it in addition to the terminal barrier assembly 104, terminal covers 118 that function to partially cover the one or more terminal access ports 120 provided on the top surface 106T of the housing 106. Terminal access ports 120 allow access and insertion of a tool 119 (e.g., a screwdriver, hex or square head tool, star tool, or the like) to tighten a terminal screw 122 into a line terminal block 124 as shown in
Now referring to
For example, the first barrier portion 110 may include first slide-in retention members 226 (
Similarly, as shown in
Referring now to
The snap-connect features may include a configuration where one feature interacts with another feature to provide some level of retention. The retention should be reversible, i.e., not so significant that the second barrier portion 114 cannot be detached from the first barrier portion 110 relatively easily, such as by prying with a screwdriver or the like.
As best shown in
As shown in
Likewise, the second barrier portion 114 may include lateral registration features configured to laterally locate the first barrier portion 110 to the second barrier portion 114. For example, as shown in
Again referring to
According to another aspect, a method of assembling an electrical switching apparatus (e.g., electrical switching apparatus 100) is provided. As shown in
The method 600 further includes, in 604, coupling a terminal barrier assembly (e.g., terminal barrier assembly 104) to the end (e.g., first end 108A), the terminal barrier assembly (e.g., terminal barrier assembly 104) including a first barrier portion (e.g., first barrier portion 110) including a first opening portion (e.g., first opening portion 112A), and a second barrier portion including a second opening portion (e.g., second opening portion 112B), wherein the first opening portion and second opening portion interface with one another to form a shielding aperture (e.g., shielding aperture 112) configured for shielding around a wire (e.g., line wire 116) extendable from the one or more electrical terminals (e.g., line terminal 121).
The method 600 may further include, in 606, receiving a wire (e.g., line wire 116) into the shielding aperture (e.g., shielding aperture 112) and shielding around the wire (e.g., around line wire 116).
The method 600 may further include, in 608, connecting the wire (e.g., line wire 116) to a terminal of the one or more electrical terminals (e.g., line terminal 121).
The above method may be implemented in any order. For example, in some embodiments, the coupling of the terminal barrier assembly (e.g., terminal barrier assembly 104) to the end (e.g., first end 108A) in 604 may take place first, then the in 606, the wire (e.g., line wire 116) may be inserted into the shielding aperture (e.g., shielding aperture 112), followed by connecting the wire (e.g., line wire 116) to a terminal of the one or more electrical terminals (e.g., line terminal 121) in 608. Connection may be by securing a terminal screw 122 of the terminal 121 via the tool 119 received through the terminal cover 118.
In other embodiments, the connecting of the wire (e.g., line wire 116) to a terminal of the one or more electrical terminals (e.g., line terminal 121) in 608 may occur first, followed by a coupling the terminal barrier assembly (e.g., terminal barrier assembly 104) to the end (e.g., first end 108A). Thus, the first barrier portion (e.g., first barrier portion 110) including a first opening portion (e.g., first opening portion 112A), and the second barrier portion including a second opening portion (e.g., second opening portion 112B) may be installed around the wire, wherein the first opening portion and second opening portion interface with one another to form a shielding aperture (e.g., shielding aperture 112) shielding around a wire extending from the one or more electrical terminals (e.g., line terminal 121).
In other embodiments, the first barrier portion (e.g., first barrier portion 110) including a first opening portion (e.g., first opening portion 112A) may be first coupled to the first end 108A of the electrical switching apparatus 100, then the line wire 116 is connected to the terminal 121 in 608, then the a second barrier portion 114 including a second opening portion (e.g., second opening portion 112B) is coupled to the first end 108A, wherein the first opening portion and second opening portion interface with one another to form the shielding aperture (e.g., shielding aperture 112) shielding around a wire (e.g., line wire 116). In some embodiments, the second barrier portion 114 may be removed to allow an inspection of the electrical connections of the line wire or line wires 116 to the terminal or terminals 121.
While the invention is susceptible to various modifications and alternative forms, specific embodiments and methods thereof have been shown by way of example in the drawings and are described in detail herein. It should be understood, however, that it is not intended to limit the disclosure to the particular apparatus or methods disclosed, but, to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the appended claims.
